For maintained spells that cancel when you click the spell button again, you can put either the spell name or "recast spell on target" into the follow-up slot. Clicking the follow-up button will cancel the spell in those cases. Since World Ablaze has a second stage when you cast it again, I don't believe it will cancel in this way. If you need to cancel it early you should be able to right-click and cancel using the icon on the spell tile.